* don't instrument a file if it has already been instrumented ([#38](https://github.com/istanbuljs/istanbuljs/issues/38)) ([9c38e4e](https://github.com/istanbuljs/istanbul-lib-instrument/commit/9c38e4e))
* use extended babylon support; adding features such as jsx ([#22](https://github.com/istanbuljs/istanbuljs/issues/22)) ([11c2438](https://github.com/istanbuljs/istanbul-lib-instrument/commit/11c2438))
* loc is sometimes not defined, so loc.start fails see [#99](https://github.com/istanbuljs/istanbuljs/issues/99) ([#18](https://github.com/istanbuljs/istanbuljs/issues/18)) ([df85ba6](https://github.com/istanbuljs/istanbul-lib-instrument/commit/df85ba6))
* function declaration assignment now retains function name ([#33](https://github.com/istanbuljs/istanbul-lib-instrument/issues/33)) ([2d781da](https://github.com/istanbuljs/istanbul-lib-instrument/commit/2d781da))
* allow an input source-map to be passed to instrumentSync() ([#23](https://github.com/istanbuljs/istanbul-lib-instrument/issues/23)) ([b08e4f5](https://github.com/istanbuljs/istanbul-lib-instrument/commit/b08e4f5))
* implement function to extract empty coverage data from an instrumented file ([#28](https://github.com/istanbuljs/istanbul-lib-instrument/issues/28)) ([06d0ef6](https://github.com/istanbuljs/istanbul-lib-instrument/commit/06d0ef6))
* hoist coverage variable to very top of file ([#26](https://github.com/istanbuljs/istanbul-lib-instrument/issues/26)) ([0225e8c](https://github.com/istanbuljs/istanbul-lib-instrument/commit/0225e8c))
* use zero-based numeric indices for much faster instrumented code ([#22](https://github.com/istanbuljs/istanbul-lib-instrument/issues/22)) ([5b401f5](https://github.com/istanbuljs/istanbul-lib-instrument/commit/5b401f5))
* guard against invalid loc ([#16](https://github.com/istanbuljs/istanbul-lib-instrument/issues/16)) ([23ebfc3](https://github.com/istanbuljs/istanbul-lib-instrument/commit/23ebfc3))